Systems are known which employ a nozzle or handpiece having a small diameter orifice to generate a jet stream as a high pressure fluid flows therethrough. Instruments specifically for use in surgical applications also have been proposed. U.S. Pat. No. 3,930,505 discloses a variable pressure jet for disintegrating eye lens tissue. A system for use in hepato-biliary surgery, known as the Hepatom, has been reported in the literature and may be available outside the United States. U.S. Pat. No. 5,370,609, and related European patent applications 0 485 133 and 0 489 496, describe a water jet catheter which delivers a high pressure liquid stream to dislodge, emulsify and remove deposits from a vein or artery.